Sony NEX-C3 Video Recording

High-definition video capture has become a must-have feature in this year's interchangeable-lens cameras, and essentially all the major manufacturers now provide some form of video capture in their compact system cameras. Being positioned as an entry-level camera, the Sony NEX-C3 forgoes more advanced features such as Full HD recording, manual exposure control, and adjustable frame rates that are sometimes found on competing models. For its target market, though, these features are likely overkill.

The few omissions are easily forgiven. While the C3 lacks Full HD video capture, its 720p mode still offers far higher resolution than standard-def camcorders and older compact cameras, which many NEX-series customers will be moving up from. While there's no manual exposure control, the NEX-C3 does offer aperture-priority exposure control, which is likely easier for consumer videographers to grasp, given that the camera itself retains control of correct exposure. NEX-C3 owners are also less likely to need to match frame rates for specific output types--they're more likely either to be reviewing movies on their computer, or burning a DVD through consumer software that will likely handle frame rate conversion with quality that's acceptable to consumers.

As an entry-level system camera, the bottom line is that Sony's NEX-C3 offers a reasonably well-considered feature set.

Compatible a wide range of Sony Alpha-mount lenses, via an accessory adapter (Depending on adapter and lens in use, autofocus may be possible, but is likely to produce audible noise and perhaps untoward focus changes in captured video.)

Some scene modes carry over into video recording, adjusting parameters for color and tone to match specific subject types

Sony NEX-C3 Video: Image Size, Frame Rate, and Encoding

The Sony NEX-C3 records just two different video resolutions, with a choice of two quality levels at the higher resolution, and records movies in MPEG-4 format with stereo AAC-LC audio. No spec is provided for the sampling rate of the audio tracks, though video players report 24 kHz at 128 kbps, regardless of resolution and quality level.

The table below shows the specs for various video recording options.

Sony NEX-C3 Video Options

MPEG-4 Format (.MP4 files)

Resolution

Frame Rate

Average Bit Rate

1,280 x 720
(16:9 aspect ratio)

30 fps (progressive)
(29.97 fps actual)

9 Mbps

6 Mbps

640 x 480
(4:3 aspect ratio)

30 fps (progressive)
(29.97 fps actual)

3 Mbps

As noted above, the Sony NEX-C3 offers only one video recording format: MPEG-4. Compared to the newer AVCHD format used in some cameras, the NEX-C3's MPEG-4 file format is a bit less efficient in its use of memory card space for a given image quality level, but is more widely supported, and seems to be a bit easier for older computers to read. Continuous movie recording is limited to approximately 29 minutes and maximum movie file size is 2GB. Sony recommends use of at least a Class 4 Secure Digital card, or a Memory Stick Pro Duo Mark 2 / Memory Stick PRO-HG Duo card to avoid issues with write speeds during video capture.

Here are some examples of video shot with our sample of the Sony NEX-C3:

Sony NEX-C3 Video-Mode Focusing

As with previous NEX-series cameras, consumer videographers will appreciate the Sony NEX-C3's live autofocus during recording. Although pros and many advanced amateurs can "pull focus" (adjust the focus manually) while filming video, and indeed may well prefer to do so, considering focus to be another means of expressing their artistic vision, it's very much a learned skill, and something few people ever manage to do really well. Without live AF, consumers for the most part are reduced to only shooting subjects at a constant distance from the camera, or to having to settle for a lot of poorly-focused video. A lot of video-capable interchangeable-lens cameras are sold to consumers these days, and while having some video capability is certainly better than none, for most consumers to make full use of a video-capable camera it really needs to be able to focus on the fly.

With the NEX series, Sony's engineers had video recording in mind from the earliest stages of development. E-mount lenses use low-mass focusing elements and high-speed stepper motors to give the rapid response required for live contrast-detect focusing during video recording. (They also employ a continuously-variable aperture mechanism, to provide stepless exposure control, another key issue for video recording.)The result is a fairly competent autofocus system that should meet the demands of most consumers, especially considering the NEX-C3's affordable pricing.

Sony NEX-C3 Video Exposure Control

While the Sony NEX-C3 lets you record movies directly from any of its still-image exposure modes, including aperture-priority, shutter-priority, and full manual exposure modes, the shutter speed, and ISO settings for video recording are always automatically controlled. While the camera's menu system might suggest full PASM (programmed, aperture-priority, shutter-priority, and full manual exposure) exposure control for videos, there in fact is no direct control over shutter speed, or ISO during movie recording.It is, however, possible to control the lens aperture, so long as you do so before capture starts.

Exposure compensation adjustments made in still-capture modes do carry over into movie recording, provided that there's enough light. (That is, if it's too dark, boosting the EV adjustment won't make your video any brighter.) White balance settings also carry over to video mode, as do the tone/color aspects of the camera's various scene modes.

Sony NEX-C3 Movie-Mode Image Stabilization

Sony's unique among camera manufacturers, in having both body-based and lens-based image stabilization technology in their product lines. In the case of the NEX-C3, image stabilization happens in the lens, so its availability will be a function of the particular lens used. Among the company's E-mount lens lineup, all of the zoom lenses offer nearly silent lens-based IS. Among the primes, only the 50mm lens offers stabilization. Using the 18-55mm kit lens, even in extremely quiet scenes, we were unable to hear any trace of the IS system in the NEX-C3's captured sound track.

Sony NEX-C3 Video: Audio recording

External Mic. The Sony NEX-C3 can accept the same optional, external stereo mic that's shown on the NEX-5 in this image.

The Sony NEX-C3 can record audio via an internal, stereo microphone, comprised of two separate microphones located on the top of the front panel, on either side of the lens mount. (Although we don't have an objective way to test this, the greater separation compared to that of the stereo mic designs in some competing models seems like it may provide better stereo effect.) The NEX-C3 also provides for recording via an external stereo microphone, attached via the same accessory socket on the camera's top that's used by the bundled mini-flash. Currently, only a proprietary Sony external mic (shown above right) can be connected to this jack. We still hold out hope that Sony will eventually offer an adapter for the common 3.5mm stereo phone plug standard, although they've yet to do so.

Sony's only published spec for the NEX-C3's audio recording capability simply says "MPEG-4 AAC-LC", so we don't officially know the sampling rate or number of bits of A/D resolution employed, although third-party MPEG players suggest a 24 KHz sample rate at 128 kbps. Audio recorded with the camera's internal mic sounded very clear, but we do no tests to measure frequency response or sensitivity, so can't comment quantitatively. We did notice that there was audible hiss in audio tracks recorded with the in-camera mic in very quiet environments, but less than we've heard on some competing models. The camera's auto-gain system also did a good job of adjusting sensitivity as sound levels got louder or softer, with no evident "breathing" in transitions from high to low sound levels.

As noted above, the AF and iris-control systems on the 18-55mm kit lens was effectively silent, in that their operation couldn't be heard on the audio track, even with no background noise. Zooming the lens could produce audible noise, as could changing our handhold on the camera or using the physical controls, but these issues could likely be mitigated significantly with the external mic accessory.

As with most of its competitors, the Sony NEX-C3 doesn't have any provision for manual audio level control, whether working from the internal or optional external mic. As is the case with the lack of a 3.5mm external jack, we don't think this will be an issue for the NEX-C3's primary target buyers. It is, however, possible to disable audio capture altogether.

Sony NEX-C3 Movie Recording/Playback User Interface

The Sony NEX-C3 makes movie recording very easy, as you can initiate it at any time, regardless of the mode-dial setting: Simply press the prominent Movie Record button with the red dot at its center at the top of the camera's rear panel, and the camera will start recording video.

Normally, this is where we'd list the Movie-mode menu items, but the NEX-C3 has no separate movie menu. In fact, the only menu items exclusively related to video recording are the choice of image size (1,280 x 720 or 640 x 480 pixels), and compression level (if recording at the higher resolution), as well as an option to disable audio recording.

Playback mode on the Sony NEX-C3 is decidedly odd, although it offers at least one feature we liked. The odd part is that the NEX-C3's playback is an either/or proposition, relative to stills and videos: If you've just shot a video and press the playback button, you'll see only movies that are stored on the card; not the still images. Likewise, if you've just shot a still image, you'll only see other stills when you hit the playback button. To switch between the two modes, you're expected to either navigate to an option on the Playback menu, or drop into thumbnail view and scroll over to the left, to select the correct tab on that screen. Alternatively, you can simply grab a throwaway exposure of the type you want to view, something we actually found much more convenient than either of the designers' intended methods. The playback mode works like this on all of Sony's NEX-series models, and although we're now very familiar with this somewhat infuriating design, it initially caused us quite some consternation. We can only imagine the dismay many new NEX-series users must experience (if only until they read the manual), when they think their once-in-a-lifetime photos disappeared after they decided to try shooting a video.

We continue to mourn the absence of a playback option that's become increasingly common on video-capable cameras; namely the "trim" function. Whenever you record a short video clip, it's almost inevitable that you'll start earlier and keep recording longer than the action you're interested in. (If you don't do this, you're almost certainly going to miss action you're interested in.) While "padding" like this is important and necessary, we like to keep our videos concise by trimming away the extraneous material at the beginning or end of the clip after they're recorded. Many cameras support doing this in-camera these days, but the NEX-C3 does not. You can certainly still import the video clips to your computer and do the trimming there, but for consumers, that's awfully cumbersome.

Essentially every video capable digital SLR/CSC currently on the market exhibits some level of motion-related distortion called rolling shutter artifacts. These are caused because the image data is captured and then read off the chip sequentially by rows, rather than each frame's data being captured all at once. In the case of the Sony NEX-C3, this means that image data for the last row of a given frame is captured and read out 1/30th second after the data for the top row was captured. The effect on moving objects is like that of a focal plane shutter in an SLR, but more pronounced, because the video frame is read out much more slowly than the slit of a focal plane shutter moves across the sensor.

For a camera that scans video frames vertically (as all do that we're aware of), rolling shutter artifacts will be most noticeable for subjects that are moving rapidly side to side, or when the camera itself is being panned horizontally. Verticals in the scene will appear tilted to the right or left, depending on the direction of camera motion. As an example, consider the case of a camera being panned from left to right, with a flagpole or other vertical object in the middle of the scene when recording for a particular frame begins: If the top of the object was centered horizontally when the first line of the video frame is acquired, by the time the last line of the frame has been captured, the bottom of the object will have shifted to somewhere left of center: As a result, the vertical object would appear to be leaning to the right.

Computer Requirements for Viewing HD Video

A typical computer these days has little trouble dealing with still images, but high-definition video can be another matter. Depending on the file format involved, it can take a pretty beefy computer to handle HD-resolution video playback without stuttering or dropping frames. The MPEG-4 image compression used by the Sony NEX-C3 is one of the more compute-intensive formats, but its maximum resolution of 1,280 x 720 pixels resolution means there's less data in each frame to deal with, than in cameras offering Full HD capture. The net result is that most reasonably recent computers should play the NEX-C3's high-def video files just fine, but you will need a relatively powerful machine for video editing.

You can of course view your movies on a high definition TV via the HDMI output. If you're still on a standard-def TV, though, you're out of luck, as the NEX-C3 doesn't offer any form of standard-def video output connectivity.